The present invention generally relates to articles for dispensing fabric laundering compositions in automatic clothes washers and dryers. Compositions which are typically added to machine clothes washers and dryers during the laundering process include detergents and fabric softener/antistatic agents. In one aspect, the present invention relates to laundering composition dispensers which provide timed release of laundering agents during the laundering cycle. In another aspect, this invention provides a fabric softener/antistatic composition which, when contained in a suitable dispenser, remains substantially inactive during the wash and rinse cycle yet dispenses during the drying cycle. The present invention also provides a detergent composition which rapidly and completely dispenses during the wash cycle when contained in the dispenser of the present invention.
Introducing laundry additives into automatic washers and dryers in specific quantities at precise intervals has long been a problem for consumers and the detergent industry. Conventional laundering techniques include measuring an effective amount of detergent to be added to the washer at the beginning of the wash cycle and repeating the step for a fabric softener/antistatic agent during the rinse cycle. Although attempts have been made to reduce the number of steps necessary to add detergent and fabric softener/antistatic agents to clothes during the laundering operation, to date these efforts have achieved only limited success. It whould therefore be desirable to provide a clean, neat, reliable method of introducing both detergent and fabric softener/antistatic agent at the beginning of the wash cycle in a single, pre-measured, disposable pouch.
Most fabric softener/antistatic compounds provide softening and antistatic action by depositing cationic particles onto fabric surfaces. They impart desirable qualities such as pleasing tactile properties, reduction of static electrically and the adherence of dirt and dust particles, reduction of fabric wrinkles and generally permit treated fabrics to be more easily separated following the drying cycle. Typically, fabric softener/antistatic compositions contain a cationic quarternary ammonia compound. These positively charged particles, however, interfere with anionic soil components as well as with anionic surfactants which are present in many conventional detergent compounds. This charge attraction between cationic and anionic components forms unwanted precipitates which may accumulate on fabric surfaces commonly in the form of redeposited soil. In order to eliminate this source of interference, it is desirable to keep anionic and cationic components separated during the laundering process.
Different approaches have been taken in the past in attempting to eliminate this charge interference. In U.S. Pat. No. 3,267,701 to Mandarino, it is suggested that fabric softener/antistat compositions be added during the drying phase only. This requires a two-step procedure for adding detergent and softener, which procedure is similarly disclosed in U.S. Pat. No. 3,947,971 to Bauer, U.S. Pat. No. 4,098,937 to Mizuno et al, and U.S. Pat. No. 4,149,977 to Morganson et al. Both Mizuno and Morganson suggest that their reusable softener dispensers be attached to dryer vanes for multiple cycles, which is impractical in laundromat-type settings.
U.S. Pat. No. 4,082,678 to Pracht et al discloses a multiple chamber pouch design with a pH-sensitive inner pouch containing a fabric softener. The outer pouch releases a pH modifier which delays solubilization of the inner pouch until the pH-neutral rinse cycle. A similar approach is taken in U.S. Pat. No. 4,108,600 to Wong where individual fabric softener particles are coated with a pH-sensitive material. U.S. Pat. No. 4,113,630 to Hagner discloses a large softener impregnated, insoluble substrate which contains a detergent.
In U.S. Pat. No. 4,203,851 to Ramachandran, detergent builder beads are impregnated with fabric softener. In U.S. Pat. No. 4,259,373 to Demessemakers et al, a double layered porous pouch releasably contains a fabric softener/antistat composition.